Blank for induction heating heads



Nov. 26, 1946.

H. E, soMEs BLANK FOR INDUCTION HEATING HEADS 5 Sheets-Sheet l Filed Dec. 30, 1943 lil 'r i l A j mf 7///.///// .i n f j. 2 .wilwwli [it y ATTORNEY Nov. 26, 1946.

3 Sheets-Sheet 2 Filed Dec. 30. 1943 Howard E. Somes Li/ I.|li M 7 INVENTOR 5% ATTORNEY Nov. 26, 1946. H. E. soMEs 2,411,699

BLANK FOR INDUCTION HEATING HEADS Filed Dec. 30. 1943 3 Sheets-Sheet 3 Patented Nov. 26, 1946 BLANK FOR INDUCTION HEATING HEADS Howard E. Somes, Detroit, Mich., assigner, by mesne assignments, to The Budd Company, Philadelphia, Pa., a corporation of Pennsylvania Application December 30, 1943, Serial No. 518,181

4 Claims. (C1. 29-190) This invention relates to induction heating heads and their manufacture, andan obiect is to standardize the manufacture of what has hereto fore always been n specialized and relatively costly operation.

The electromagnetic induction heating of interior surfaces such, for example, as the inner walls of cylinders, tubes, hubs', and the like. usually requires a head consisting oi' a coil supporting mandrel on which a suitable core is mounted and a heating coil wound around the cord. An electric current conducting arbor is connected to and supports the mandrel, the mandrel and arbor members being electrically insulated from each other. One terminal of the mandrel-supporting coil is connected to the arbor member, while the other terminal is connected to the man drei. The mandrel and arbor members are, in turn, electrically connected to conductors leading to the opposite sides oi a transformer coil for supplying heat inducing current to the working coil on the mandrel.

Inasmuch as the heating operation in which the heating head is employed usually requires a relatively close clearance between the heating coil and the surface oi' the workpiece, and inasmuch as. in the case oi' internal heating, the entire heating head must usually be passed ens tirely through the bore of the workpiece, it has been customary heretofore tol individually design and manufacture each heating head according to the particular dimensions required for treating a specific workpiece. is process has required the special manufacture of each head and of its component parte.

A further object of this invention is to provide a standardized form of blank from which various sizes of induction heating heads can be easily and cheaply manufactured by ordinary machine operations.

These and other objects which willbe apparent are accomplished by the invention hereinafter described and illustrated in the accompanying drawings in which:

Fig. l ie a transverse sectional view' illustratingv one embodiment of a relatively small diameter induction heating head which can be produced by the present invention;

Fig. 2 is a broken side elevation of e. headiorrning blank constructed in accordance with one embodiment of this invention, i'rom which the head illustrated Fig. can be made:

Fig. 3 is a transverse sectional view ou4 the line I-l of Fig. 2; vliixlmiisascctionontheline-Ioflilsnt;

Fig. 5 is a view similar to Fig. l illustrating a different head construction produced by this invention;

Fig. B is a section through a heating head blank employed in making the head oi Fig. 5;

Fig. 7 is a view similar to Figs. 1 and 5 illustrating a still different head construction produced by this invention;

Fig. 8 is a sectional view of the blank employed in making the head of Fig. 7, and

Fig. 9 is a section on the line 9--9 of Fig. 8.

In the present invention a heating head blank is formed by separate arbor and mandrel torming members which are connected together in substantial axial alignment by electrical insulating material interposed between and connecting together the two members, Interlocking surfaces are formed between the two members and the insulation so as to form a rigid unitary blank structure. The arbor and mandrel forming members are constructed and arranged to be shaped any required size and configuration to a desired nnished head by conventional machining operations, to adapt the mandrel for supporting a suitable coil and core, and to adapt the arbor member for connection to suitable current conducting and supporting members.

In actual practice, it may be found expedient to form a series of blanks ci' different sizes, each blank being adapted to form a series oi different sizes of heating heads by machining down to any required dimensions less than those of the original blank. For example, a given blank can be used to produce a head having substantially the same dimensions as the blank, or it can be machined down to produce a head of any lesser diameter. Therefore, instead of forming a single heed blank capable of producing the largest di ameter head and turning it down to provide the smallest diameter head, which would require the removal oi an excess amount of metal with resulting waste, it will be found desirable to provide a series of blanks ci diii'ereut sizes, each blank being adapted to be turned down a reasonable amount to provide heads oi less diameter than the original blank.

In that embodiment of the invention which is illustrated in FiZs. l to 4, a head forming blank is shown comprising a mandrel forming member H having an enlarged portion or collar i2 formed thereon adjacent one end. An axial bore Il extends inwardly irom the end adjacent the collar i2 to a point within the collar where it intersects a radial bore il extending inwardly from the side of the mandrel forming member l I.

`An arbor-forming member I5 has a tapered end I6 adapted to be mounted in the axial bore I3 of the mandrel member I I. A radially extending enlargement or boss I1 on the end of the tapered portion I6 is positioned so as to project into the radial bore I4 of the mandrel member. The arbor-forming member I5 has an axially extending bore I8 extending inwardly from the outer end thereof to a point beneath the boss il.

In forming the blank, the tapered end le of the arbor member IE is positioned `in the axial bore I3 of the mandrel member and the two members mounted in axial alignment with the boss I1 extending into the radial'bore i4 of the mandrel member. Electrical insulating material in the iorm of a sleeve i9 surrounds the tapered arbor end I6 within the mandrel bore and the boss I'I is similarly electrically insulated fromthe mandrel member by insulation 2l.

Both the arbor and mandrel forming members are preferably formed by casting a suitable current conducting copper alloy, or beryllium or other suitable metal. Preferably, the insulation i9 is a plastic which can be cast or molded in place between the assembled arbor and mandrelforming members to join such members integrally together. As evident from Figs. 3 and 4, the arbor and mandrel members and the insulation have interlocking portions which results in all parts of the blank being rigidlyconnected together so that the finished blank can be readily termed into a heating head ci any smaller size and connguration by conventional machining operations. For this purpose the insulation I9 is provided with a shoulder 5 engaging the end of the mandrel forming member i i, while the end of the insulation engages the shoulder t formed at the base of the tapered portion l@ of the arbor le. Indexing slots 22 and Mare formed in the mandrel and arbor members, respectively, in order to properly positionthem during the in', sulation molding operation so that the boss il will be properly centered in the radial bore id.

Fig. 1 illustrates a solid mandrel type oi heatv ing head for which the blank shown in Figs. 2 and 3 is especially adapted. For 'this purpose, the mandrel portion ii is turned down to puede-I termined diameter and is given. a threaded end 2d with. an axial opening 25 drilled into the and. for a short distance. The inner end of the turned face is provided with a dovetailed groeve Si@ to receive the dovetailed projections il on the radially tapered laminations 2li forming the core on which the tubular heat inducing coil 2e is wound. The laminated core is secured in place by a washer 3l, having a groove 32 engaging the dovetailed projections 33 at the lower ends o the laminations, pressed into place by a nut or similar Sitting 3S. In turning down the mandrel mem ber Il to the desired diameter, the shoulder i l and adjacent end of the mandrel member are also turned down to predetermined sise, and the projecting arbor member l5 is also turned down and provided with threads 35, the insulation le above the shoulder being turned down, but a thin layer being left for insulation purposes. The boss I1 is drilled to form a bore 3d communicating with the inner end of the axial passage it, and the insulation I9 at the bottom of the bore I4 is grooved to provide a groove 31.

The lminations 28 are then stacked in place around the mandrel Il and the coil 29 wound around the laminated'core after the blank has been machined to the desired shape and size. The upper end 38 of the coil is extended through the insulated groove 31 and is secured in the radial bore 3S leading to the axial bore I8 of the arbor member. A radial passage 39 drilled in the lower end of the arbor member-II to connect with the axial passage 25 is connected to the lower end of the tubular coil 29 to provide a continuous passage for the now ci coolant therethrough. As usual, a layer of insulation 4I is located between the 4various coil turns and the laminated core 28, while layers of insulation d separate the various turns from each other.

The connection between the lower end of the coil and the radial opening de also electrically connects this end of the coil with the mandrel member El.

It will be apparent that the nished head of Fig. 1 can be made from the blank shown in Figs. 2 and 3 by simple inexpensive operations, and that the blank shown can be used to produce heads of varying size. The broken outline shown in Fig. 1 indicates approximately the largest size of head which would ordinarily be made bythe blank of Fig. 2, while the solid lines show approximately the smallest diameter head.

The finished head will ordinarily be connected in place by threading the arbor member I5 into a threaded socket formed in the lower end of a supporting electric conductor de having a bore d5 .for conveying coolant tothe head. An outer current conducting sleeve dii has contact iingers dl extending downwardly therefrom to electrically contact the upper end of the mandrel I I above the shoulder i2. This establishes an electric circuit from the conductor ed through the arbor member l5, coil 29, mandrel member II, n'gers el, and outer conductor member et. A sleeve 48 of insulation surrounds the conductor N and cooperates with the upper end o the insulation i9 of the blank toentirely enclose the inner conducting members.

Figs. 5 and illustrate the application of the invention to the manufacture of a dierent form of heating head. As shown in Fig. 6, the manl drel-forming member II is provided with an axial bore 5I extending entirely therethrough, arborniorming member le has an axial bore 52 extending entirely through that member, so that the finished blank has an axial bore entirely through the blank from end to end. That portion of the bore 5l passing through the enlarged section i2 is somewhat en largd over the remaining portion of the bore to receive the insulation i9 which ispreferably molded in place to join the two members. As in the case of the blank illustrated in Figs. 2 and 3, the arbor member I5 has a boss il projecting into the radial bore I and surrounded by insulation which locks the parts together against relative rotation or longitudinal movement. The shoulder forming collar Ei on the insulation engages the end of the inarudrelv member II while the upper end of the insulation abuts the shoulder a on the arbor member i5, similar to the blank of Fig. 3. The lower end ofthe arbor member l5 engages a shoulder l on the surrounding insulation I9 which, in turn, engages-a shoulder 3 on the inner bore of the mandrel member.

Fig. 5 shows the type of hollow heating head for which the blank of Fig. 6 is particularly adapted. The mandrel member l l is turned down to the form shown and the inner bore is enlarged slightly and a beveled shoulder 62 formed on the bottom of the arbor member. The same laminations 28 are secured in place by a washer 53 held in place by a Split ring 5d keyed in a slot 55 cut in the outer face of the lower end o! the reduced mandrel member I I The tubular coil 29 is wound in place and insulated in the manner above described, the upper end 38 extending through the insulated groove 31 and secured in the radial bore 99 formed in the boss I1 and connected with the axial bore 52 of the arbor member I5. The lower end of the heating coil is secured in or connected to the radlalopening 99 in the lower end of the mandrel member II. This opening communicates with an inner chamber 59 in the inner wall of the arbor member I I.

The head shown in Fig. 5 is supported in place, with the upper end of the arbor member I5 positioned in a socket 51 in an electric current conducting member 59, by a tubular supporting member 59 which has a lower collared end 9| engaging the shoulder 92 formed at the lower end of the arbor member I5 within the mandrel member |I. The tubular supporting member 59 is moved into position through the axial bore 5| oi' the mandrel member and its outer diameter is for the greater part sulllciently less than the diameter of the axial passage 52 in the arbor member I5 to provide space for the flow of coolant therebetween. The tubular supporting member 59is held in place within the heating head by a tube 93 o! insulating material having a head 94 vulcanized to an annular collar 95 which is rotatably keyed in the upper end of a sleeve 96 extending downwardly through the axial passage 5| and having a threaded end 91 threaded in part to the lower end of the mandrel member. A fitting 98 threaded to the projecting end of the sleeve 91 and engaging the end of the mandrel member Il acts as a lock nut to secure the parts together. The sleeve 99 has a plurality of radial `passages 1| through which coolant tiows through the lower end of the tubular coil 29 to the interior-of the sleeve 99 and outwardly through a ball valve 12. l

In the form shown in Fig. 5, the conductor 51 is electrically connected to one end of the coil through the arbor member I5 while the other endof the coil is electrically connected, through the mandrel and contact lingers 19 engaging the upper surface of the mandrell II, with the outer conductor 14 surrounding and insulated from the inner conductor 51 by an insulating sleeve 15. A ring 19 of insulation material cooperates with the lower end of sleeve and with the upper end of the lblank insulation I9 to entirely enclose the lower end of the conducting member 58.

As in the case oi the blank illustrated in Figs. 2 and 3, that shown in Fig. 6 is also formed by casting the arbor and mandrel members from any suitable conducting material and then joining them together by means of the intervening insulation I9, preferably molded as described. The blank of Fig. 6 can be employed to make a series of induction heating heads ranging in size from that shown by the broken lines of Fig. 5 to the smaller size fully illustrated in solid lines. To do so, the blank of Fig. 6 is machined to required shape and size, the laminations 28 are stacked in place around the mandrell II to provide the supporting core, and the coil 28 is wound thereon and insulated therefrom. The various supporting iittings are mounted in position at the time the head is secured to the supporting conductors. In this type of heating head, there is a continuous ilow of coolant through the heating coil, being delivered thereto through the annuiar passage between the tubular supporting member 59 and the axial passage 52 in the arbor oi' the mandrel member.

member I5, thence to the upper end ofthe tubular coil 98, then through the coil and outwardly through the lower end thereof to the chamber 59, radial passages 1| and interior of the sleeve 99 from which it nows outwardly through the hollow vinsulating tube 99 and supporting tubular member 99. Under certain conditions of use, the ball valve 12 will be opened to permit accelerated ilow of coolant through the conductor 29 by accelerating the discharge downwardly through the ball valve.

Figs. 8 and 9 illustrate a somewhat modified form of blank for use in forming the hollow heating head shown in Fig. 7. In this form a mandrel member 8|V having a bore 92 extending therethrough is provided with a radial bore 83 intorsecting the axial bore about midway ofthe length 'I'he upper end 84 of the mandrel member is of reduced outside diameter. An elongated arbor member 85 having an axial bore 89 extending therethrough is telescoped within one end of the mandrel member to which it is joined by an intervening tube 91 oi insulation which surrounds a portion of reduced diameter and engages a shoulder 81 on the arbor member and a shoulder 81 on the mandrel member. Opposite the radial bore 83, the arbor member is provided with a thickened'cross-section 88, and the insulating material has a rectangular enlargement 89 interlocking with recesses 9| and92 in the mandrel and arbor members for locking the parts against relative rotation and longitudinal movement.

The blank shown in Fig. 8 is .particularly adapted i'orthe construction o! heating heads of relatively large diameter such, for example, as the head shown in Fig. 7. In this form, the blank is ilrst turned to the diameter and configuration shown, the reduced end 84 of the mandrel member being provided with threads 93, and an annular shoulder 94. The threaded opening 95 is formed in the large portion 88 and the insulation fllling the bore 89 is out and shaped as shown. In this form, in order to obtain the desired diameter of heating coil, a spacer ring 99 is mounted on the outer face of the mandrel member 8| and is supported on the shoulder 94. The spacer is held against rotation by a key 95 engaging a key slot 99 in the spacer. The outer face of the spacer ring 99 has a dovetailed slot 91 for receiving the similarly shaped projections on the laminations 98 which 'are stacked around the ring 99 and held in place thereon by a fastening ring 99 secured in piace by a clamping ring i0| threaded to the threads 93 on the mandrel member. The tubular heating coil |02 is wound on the core and insulated therefrom in the usual way, the upper end |03 of the coil fitting into a sleeve connector |04 extending into and secured in the threaded opening 95 of the arbor member through the surrounding insulation 97, and the lower end of the coil is secured to a similar sleeve connector |05 secured in a threaded opening |09 in the mandrel member 8|.

When in use, the head of Fig. 'l as above ccnstructed, is supported on the tubular supporting member |01 adapted to be inserted through the bottom or the head and having a shouldered end |08 engaging the lower face of the arbor member 95, the outer diameter of the tubular supporting member |01 being suiiiciently less than the axial bore 99 of the arbor member 85 to form a uld passage |09 communicating with the upper end of the coil |03 through the hollow connector |04. A tubular insulating member I I0 extends upward- 

